Naval Market - Italy

Italy -
  • Acoustic reduction


Anyone who has been within hearing distance of any type of passing marine vessel will understand immediately that noise and the control of noise is a major priority, not only to those on board but also for marine designers, engineers, operators,observers and users alike.

Comfort on board, particularly as far as “pink” or ambient “noise” is concerned, has become a common focal point for shipbuilders, passengers, shipyards and Classifi cation Registers of Shipping.

As these various parties aim their attention at the control of noise, regulations to control noise have become increasingly strict. This is understandable and the trend is likely to continue in the years ahead.

For example, the noise limit set for a “suite or mini suite”, no matter where it is situated, is prescribed at 45 dB(A).

If this room is located close to a “dancing room” or an “engine room”, where it is possible to register inside noise levels of 107-115 dB(A) or above, noise abatement measures must aim to bring noise levels down by 65 dB(A) or better.

This is easier said than done simply because it is difficult to project and realise insulation levels required under actual running conditions, particularly when infl uential ingredients such as weight, thickness and cost are critical and have to be factored in to the overall equation.

It is therefore necessary to use materials which not only have excellent sound-insulating performances but also dampening visco-elastic characteristics.

These characteristics, among others shown in the relevant technical data sheet, are those that makePROMASOUND® TL a real innovation in the naval and marine field.

Better Than Other Sound Abatement Solutions

Under the same conditions, PROMASOUND® TLof 1.5mm thickness on a 6mm steel wall treated with rock wool, produces an insulation higher by 1dB than a 0.5mm lead plate (used before), with a weight reduction of 2.5–2.7kg/m2.
From the 1970s until even today it is quite common to see large amounts of lead (Pb) laminated in thin plates in use in the naval and marine sector. After all, lead is an easy material to work and a very good insulator although it does not have significant visco-elastic properties.

Lead also has a very high specifi c weight of 11.34kg/m2/mm of thickness and melts at 327.4°C. However, it has a greylight blue colour, which oxidises easily on contact with normal atmospheric conditions. 

As such, lead is rapidly covered with a “blackish” layer of oxide easily absorbed by people through direct contact or via air circulation in the form of detached particles (of lead oxide) following persistent vibration, collision or other accidental causes. 

Lead and all its compounds are well known to be poisonous. For instance, workers who handle rolled lead sections or its compounds can be subject to accumulation phenomena. The subsequent chronic poisoning, known as professional illness, is 
categorised under the name of saturnism. 

In order to avoid these risks, strict preventive health measures have been in place for quite some time and in many cases have been legislated into formal compulsory laws. Even though it is evident that the most effi cient prevention consists of strong usage reduction of lead in the industrial field, it is very reassuring indeed thatPROMASOUND® TL easily fulfils most sound abatement tasks, among others.